|Week|Date|Opponent|Score|Result|Record|
|---|---|---|---|---|---|
|1|July 9|vs. Saskatchewan Roughriders|31–21|Win|1–0|
|2|July 16|at Montreal Concordes|36–0|Win|2–0|
|3|July 24|vs. Hamilton Tiger-Cats|36–25|Loss|2–1|
|4|Aug 1|at Edmonton Eskimos|32–26|Win|3–1|
|5|Aug 8|vs. BC Lions|29–16|Win|4–1|
|6|Aug 20|at Calgary Stampeders|35–4|Win|5–1|
|7|Aug 28|vs. Ottawa Rough Riders|27–20|Win|6–1|
|8|Sept 5|at Saskatchewan Roughriders|36–35|Win|7–1|
|9|Sept 11|vs. Calgary Stampeders|15–11|Loss|7–2|
|10|Sept 18|at Ottawa Rough Riders|38–28|Loss|7–3|
|11|Sept 25|vs. Montreal Concordes|19–16|Win|8–3|
|12|Oct 2|at BC Lions|29–19|Win|9–3|
|13|Oct 11|vs. Toronto Argonauts|39–35|Win|10–3|
|14|Oct 17|at Toronto Argonauts|29–16|Win|11–3|
|15|Oct 23|vs. Edmonton Eskimos|33–17|Loss|11–4|
|16|Nov 7|at Hamilton Tiger-Cats|24–21|Loss|11–5|

Question: how many teams played them in october?
Answer: 4